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The elements involved in an electrochemical reaction are characterized by the number of electrons each has. The oxidation state of an ion is the number of electrons it has accepted or donated compared to its neutral state (which is defined as having an oxidation state of 0). If an atom or ion donates an electron in a reaction its oxidation state is increased, if an element accepts an electron its oxidation state is decreased.
For example when sodium reacts with chlorine, sodium donates one electron and gains an oxidation state of +1. Chlorine accepts the electron and gains an oxidation state of −1. The sign of the oxidation state (positive/negative) actually corresponds to the value of each ion's electronic charge. The attraction of the differently charged sodium and chlorine ions is the reason they then ionicly bond to each other.
The loss of electrons of a substance is called oxidation, and the gain of electrons is reduction. This can be easily remembered through the use of mnemonic devices. Two of the most popular are "OIL RIG" (Oxidation Is Loss, Reduction Is Gain) and "LEO says GER" (Lose Electrons: Oxidization, Gain Electrons: Reduction). The substance which loses electrons is also known as the reducing agent, or reductant, and the substance which accepts the electrons is called the oxidizing agent, or oxidant. The oxidizing agent is always being reduced in a reaction; the reducing agent is always being oxidized.
A reaction in which both oxidation and reduction is occurring is called a redox reaction. These are very common; as one substance loses electrons the other substance accepts them.
Oxidation requires an oxidant. Oxygen is an oxidant, but not the only one. Despite the name, an oxidation reaction does not necessarily need to involve oxygen. In fact, even fire can be fed by an oxidant other than oxygen: flourine fires are often unquenchable, as fluorine is an even stronger oxidant (it has a higher electronegativity) than oxygen).
In the 1960s– 1970s quantum electrochemistry was developed by Revaz Dogonadze and his pupils.
The International Society of ElectrochemistryThe International Society of Electrochemistry (ISE) is a world-wide scientific Society founded in 1949. The Head Office of ISE is located now in Lausanne ( Switzerland). ISE is a Member Organization of IUPAC. The Society has now more than 1100 Individual (ISE) was founded in 19491949 is the common year starting on Saturday. see link for calendar) Events January-February January 4 RMS Caronia of the Cunard Line departs Southampton for New York on her maiden voyage January 4 February 22 Series of winter storms in Nebraska, Wyoming,.
A spontaneous electrochemical reaction can be used to generate an electrical currentIn electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. Conventional current was defined early in the history of electrical science as a flow of positive charge, although we now know that, i, in electrochemical cellAn electrochemical cell is a setup used for creating an electromotive force in a conductor separating two reactions. The current is caused by the reactions releasing and accepting electrons in to the different ends of the conductor. The most common exampls. This is the basis of all batteriesIn science and technology, a battery is a device that stores energy and makes it available in an electrical form. Although such storage in an electrostatic form is practical in some specialized uses, batteries usually consist of electrochemical devices su and fuel cellA fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. it produces electricity from an external fuel supply as opposed to the limited is. For example, gaseous oxygen (O2) and hydrogen (H2) can be combined in a fuel cell to form water and energy (a combination of heat and current, typically).
Conversely, non-spontaneous electrochemical reactions can be driven forward by the application of a current at sufficient voltage. The
electrolysisThis article is about the chemical process. Electrolysis is also a method of epilation. In chemistry and manufacturing, electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. Overview The source m of water into gaseous oxygen and hydrogen is a typical example.